Genetics Ch.8: Variation in Chromosome Structure and Number

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  1. Which of the following descriptions of chromosomes is not correctly matched?
    A) Submetacentric — chromosome arms are slightly different in size.
    B) Acrocentric — chromosome arms are identical in size.
    C) Metacentric — chromosome arms are almost equal in size
    D) Telocentric — there is only one chromosome arm.This is a correct
    description of a telocentric chromosome.
    D) Telocentric — there is only one chromosome arm.This is a correct description of a telocentric chromosome.
    (this multiple choice question has been scrambled)
  2. Which of the following is not a type of chromosomal mutation?
    A) Translocation
    B) All of these are chromosomal mutations.
    C) Inversion
    D) None of these are chromosomal mutations.
    E) Duplication
    B) All of these are chromosomal mutations.
    (this multiple choice question has been scrambled)
  3. A duplication is:
    A) The presence of an extra copy of an existing chromosome.
    B) A piece of genetic material which has been moved to a new chromosome.
    C) The presence of an extra copy of a piece of chromosomal material.
    D) The result of chromosomal material exchanged between two chromosomes.
    E) The presence of an entirely new piece of chromosomal material.
    C) The presence of an extra copy of a piece of chromosomal material.
    (this multiple choice question has been scrambled)
  4. Which explanation for the loss of a terminal piece of a chromosome makes the
    most sense?
    a) Only pieces of DNA with centromeres are correctly sorted into daughter nuclei
    during mitosis.
    b) Only pieces of DNA with telomeres are correctly sorted into daughter nuclei
    during mitosis.
    c) This piece of DNA is recognized as foreign by the cell.
    d) A and B
    e) None of these.
    a) Only pieces of DNA with centromeres are correctly sorted into daughter nuclei during mitosis.
  5. Which technique can be used to quickly identify large deficiencies?
    A) All of these.
    B) Genetic studies.
    C) Pedigree analysis.
    D) None of these.
    E) Karyotype analysis.
    E) Karyotype analysis.
    (this multiple choice question has been scrambled)
  6. Why might gene duplication allow for generation of more genetic variability?
    a) The second copy of the gene could be expressed under different regulation.
    b) The second copy of the gene could accumulate mutations which would be lethal if
    only one copy were present.
    c) The second copy of the gene could be deleted without effect on the organism.
    d) A and B.
    e) None of the above.
    d) A and B.
  7. Which statement regarding the human globin genes is likely to be correct?
    a) Myoglobin is probably more similar to α-globin than is β-globin.
    b) α-globin and β-globin are probably more similar to each other than they are to
    myoglobin.
    c) The globin genes in mice are probably more similar to those of humans than are
    globin genes of chimpanzees.
    d) All of these.
    e) None of these.
    b) α-globin and β-globin are probably more similar to each other than they are to myoglobin.
  8. Which of the following chromosomal rearrangements would you expect to have the
    least phenotypic effect on the organism?
    A) A duplication.
    B) A paracentric duplication.
    C) A deficiency.
    D) A paracentric inversion.
    D) A paracentric inversion.
    (this multiple choice question has been scrambled)
  9. Why are unaffected carriers of inversions likely to produce genetically abnormal
    progeny?
    a) The inversion chromosome is more likely to be placed in a gamete than the normal
    chromosome.
    b) The inversion chromosome is unable to accomplish synapsis with the normal
    chromosome during meiosis.
    c) Crossovers cannot occur between inversion and normal chromosomes.
    d) Crossovers between the inversion and normal chromosomes lead to chromosomes with
    deletions, deficiencies, or abnormal structure.
    • d) Crossovers between the inversion and normal chromosomes lead to chromosomes with
    • deletions, deficiencies, or abnormal structure.
  10. What do deficiencies, inversions, and translocations have in common?
    A) They all involve extra genetic material in a karyotype.
    B) They all can be caused by DNA breakage and inaccurate repair.
    C) They all involve loss of genetic material.
    D) They all contain normal amounts of genetic material in unusual arrangements.
    B) They all can be caused by DNA breakage and inaccurate repair.
    (this multiple choice question has been scrambled)
  11. What do inversions and balanced translocations have in common?
    A) They both contain a normal amount of DNA.
    B) They both tend to cause abnormal gamete production.
    C) They both tend to have mild or no phenotypic consequences.
    D) All of these.
    E) None of these.
    D) All of these.
    (this multiple choice question has been scrambled)
  12. Which of the following is an example of a euploid individual?
    A) None of these.
    B) A human with 47 chromosomes.
    C) A D. melanogaster embryo with 7 chromosomes.
    D) A plant of a new wheat species with twice the usual number of chromosomes.
    D) A plant of a new wheat species with twice the usual number of chromosomes.
    (this multiple choice question has been scrambled)
  13. Which of the following terms could be used to describe the individual whose
    karyotype is shown in Fig 8.1c?
    A) Tetraploid
    B) Aneuploid
    C) Diploid
    D) Monosomic
    C) Diploid.
    (this multiple choice question has been scrambled)
  14. If X inactivation in humans shuts down extra X chromosomes, why do XXY and XXX
    individuals show any phenotypic effects?
    A) Some X linked genes escape inactivation.
    B) The extra Barr body takes up physical space in the cell.
    C) None of these.
    D) X inactivation can only shut down one X per cell.
    E) All of these.
    A) Some X linked genes escape inactivation.
    (this multiple choice question has been scrambled)
  15. Which of the following might cause nondisjunction?
    A) Lack of synapsis im mitosis.
    B) Failure of synapsis in meiosis I.
    C) Chromosome breakage.
    D) Centromere duplication.
    B) Failure of synapsis in meiosis I.
    (this multiple choice question has been scrambled)
  16. An allotetraploid species:
    A) All of these.
    B) may be agriculturally important.
    C) is likely to be able to produce viable gametes.
    D) contains a full diploid set from each of two related species.
    E) None of these.
    A) All of these.
    (this multiple choice question has been scrambled)
  17. Deletions tend to be less harmful than duplications.
    a) True
    b) False
    b) False
  18. Members of a gene family may be created by abnormal crossing over.
    a) True
    b) False
    a) True
  19. Inversions tend to have more serious phenotypic effects than other chromosomal
    rearrangements.
    a) True
    b) False
    b) False
  20. Alternate and adjacent-1 segregation are equally likely to produce nonviable
    gametes.
    a) True
    b) False
    b) False
  21. Aneuploidy is usually a lethal condition in humans.
    a) True
    b) False
    a) True
  22. While plants can often exist as polyploid species, animals cannot.
    a) True
    b) False
    b) False
  23. All of the cells within an individual are genetically identical.
    a) True
    b) False
    b) False
  24. An allodiploid can be created by fusion of diploid gametes.
    a) True
    b) False
    b) False
  25. Comparative genomic hybridization is used to detect
    A) chromosome deletions.
    B) chromosome duplications.
    C) both A and B.
    D) chromosome loss.
    C) both A and B.
    (this multiple choice question has been scrambled)
  26. In comparative genomic hybridization, if the green to red ratio is greater than
    one, this suggests a
    A) change in chromosome number.
    B) chromosome deletion.
    C) chromosome duplication.
    d) none of the above.
    C) chromosome duplication.
    (this multiple choice question has been scrambled)
  27. In the comparative genomic hybridization experiment of Kallioniemi and Pinkel,
    the green DNA was from cancer cells and the red DNA was from
    A) a sample of normal cells.
    B) a different sample of cancer cells from a different patient.
    C) a different sample of cancer cells from the same patient.
    d) none of the above.
    A) a sample of normal cells.
    (this multiple choice question has been scrambled)
  28. In comparative genomic hybridization, which samples are fluorescently labeled?
    A) Only A and B
    B) The cancer DNA
    C) The metaphase chromosomes
    D) The normal DNA
    A) Only A and B
    (this multiple choice question has been scrambled)
  29. In the data of Figure 8.8, a deletion was observed in the short arm of
    chromosome 9. Let's suppose a researcher made a mistake and added twice as much
    of the normal DNA compared to the cancer DNA. In this deleted region of
    chromosome 9, the ratio of green to red fluorescence would be
    A) 1.0
    B) 0.75
    C) 0.25
    D) 0.5
    C) 0.25
    (this multiple choice question has been scrambled)
  30. homologous
    describes the analogous chomosomes from evolutionarily related species.
  31. paracentric inversion
    an inversion in which the centromere is found outside of the inverted region
  32. telomere
    specialized DNA sequences found at the ends of eukaryotic, linear chromosomes
  33. euploid
    describes an organism in which the chomosome number is an exact multple of chomosome set
  34. triploid
    a organism or cell that contains three sets of chromosomes
  35. polyploid
    an organism or cell with three or more sets of chromosomes
  36. nondisjunction
    event in which chromosomes do not segregate properly during mitosis or meiosis
  37. monoploid
    an organism with a single set of chromosomes within its somatic cells
  38. polytene chromosome
    chromosomes that are found in certian cells, such as Drosophilia salivary cells, in which the chomosomes have replicated many times and the copies lie side by side
  39. chromocenter
    the central point where polytene chomosomes aggregate
  40. chromomere
    a dark band within a polytene chromosome
  41. meiotic nondisjunction
    condition in which chromosomes do not segregate equally into the gametes during meiosis
  42. alloploid
    an event in which chromosomes do not segregate equally during mitosis
  43. mosaicism
    when the cells of part of an organism differ genetically from the rest of the organism
  44. autopolyploid
    a polyploid produced within a single species due to nondisjunction
  45. allopolyploid
    an organism that contains two or more sets of chromosomes from two (or more) species
  46. homeologous
    describes the analogus chromosomes from evolutionarily related species
  47. cell fusion
    describes the process in which individual cells are mixed together and made to fuse
  48. heterokaryon
    a cell produced from cell fusion that contains two separate nuclei
  49. heterosis
    Heterosis is usually different from over dominance because the hybrid may be heterozygous for many genes, not just a single gene, and because the superior phenotyp may be due to the masking of deleterious recessive allels.
  50. genetic variation
    genetic differences among members of the same species or among different species
  51. chromosome mutation
    a substantial change in chromosome structure that may affect more than a single gene.
  52. genome mutation
    a change in chromosome number
  53. metacentric
    describes a chromosome with the centromere in the middle
  54. submetacentric
    describes a chromosome in which the centromere is slightly off center
  55. acrocentric
    describes a chromosome with the centromre significantly off center, but not at the very end.
  56. telocentric
    describes a chromosome with its centromere at one end
  57. karyotype
    a photographic representation of all the chromosomes within a cell. It reveal how many chromosomes are found within an actively dividing somatic cell.
  58. deficiency
    condition in which a segment of chromosomal material is missing
  59. deletion
    condition in which a segment of chromosomal material is missing
  60. duplication
    the copying of a segment of DNA
  61. inversion
    a change in the orientation of genetic material along a chromosome
  62. translocation
    when one segment of a chromosome breaks off and becaomes attached to a different chromosome
  63. pseudodominance
    a pattern of inheritance that occurs when a single copy of a recessive allele is phenotypically expressed because the second copy of the gene has been deleted from the chromosome
  64. polytene chromosomes
    chromosomes that are found in the certian cells, such as Drosophila salivary cells, in which the chromosomes have replicated many times and the copies lie side by side
  65. position effect
    a change in phenotype that occurs when the position of a gene is changed from one chromosomal site to a different location
  66. gene family
    two or more different genes that are homologous to each other because they were derived from the same ancestral gene
  67. protoplast
    a plant cell without a cell wall
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Genetics Ch.8: Variation in Chromosome Structure and Number
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Genetics Ch.8: Variation in Chromosome Structure and Number
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